Anchor



June 9, `1953 R. s. DANFORTH 2,641,215

ANCHOR Filed Jan. 21. 1949 2*,sneet'S-sneet 1 PIE-L 4.1 A? ATTOR/VE June 9, 1953 I y R. s. DANFQRTH 2,641,215

ANCHOR Filed Jan, 21. 1949" l 2 sheets-smeet 2v J Y l IN V EN TOR.

Richard 5. Danfor ATTORNEY Patented June 9, 1953 ANCHOR Richard S. Danforth, Berkeley, Calif., assigner to Robert H. Eckhoff, Piedmont, Calif., as trustee Application January 21, 1949, Serial No. 71,989

6 Claims.

This application is a continuation-in-part of my earlier nled application, Serial No. 43,429, nled August 10, 1948.

This invention relates to an improvement in twin nuke anchors, particularly anchors constructed in accordance with one or more of my prior Patents 2,249,546, 2,282,566 and 2,320,966.

The so-called twin fluke anchor includes a shank and twin nukes, usually secured together as a unit and pivoted at one end of a shank whereby both nukes engage the ground simultaneously; the anchor may include a stock at either end of the shank although it is common to pivot the nukes and shank on thestock so the latter is provided at the after end of the shank.

When such an anchor is cast overboard from a boat or ship and is permitted to fall upon bottom, the pull provided by the attached cable draws the anchor over the bottom. To insure that the nukes engage bottom positively and without too much loss of time, it is usual to provide, at the after end of the anchor, a structure to facilitate movement of the nukes into operating position and engagement with the bottom. This structure, usually termed the crown, has included arrangements of both arcuate and plane surfaces extending upwardly more or less directly from the plane of the nukes for a considerable distance above such plane, it being the purpose of these surfaces to insure that the anchor engages bottom promptly with the nukes disposed relative to the shankin their nnal operative position.

When such an anchor is disengaged or brokenout from bottom and is drawn to the surface, it is usual for the anchor to carry with it, particularly from a mud or clay bottom, a relatively large mass of the bottom. This increases the load on the anchor cable to a very considerable extent. On small anchors which can be handled alone by hand and which are usually brought on board the boat and are not carried in a hawse pipe, the use of a winch is frequently made essential because of the load added to the anchor by the mud or clay fouling the crown portion of the anchor; on small anchors weighing less than twenty pounds, I have observed mud and clay fouling the nukes, crown and shank of such mass that the anchor load could not be easily handled by hand and brought on board without a winch.

Based upon my investigations, studies, and findings, I have determined that by providing a crown structure, as will be hereinafter described, the anchor can be broken-out of bottom engagement with relative ease and, when broken-out, is comparatively free of bottom, for mud or clay do not stick to the anchor to any appreciable extent. As a consequence, the anchor can be handled with greater ease and less effort. In addition, I have found that the crown construction of the present invention insures that the anchor engages bottom with great rapidity and digs into the bottom almost immediately upon contact. This is also important, for in soft mud, or clay, particularly those containing so much water as to have a consistency comparable to that of pea soup, an anchor may noat.

I have found that the crown of the anchor, particularly one constructed in accordance with one or more of my aforementioned patents, should be provided by two plates which should be disposed on both sides of the nuke pivot and must slope upwardly and toward the rear of the anchor from the plane of the nukes at a relatively acute angle one within the range of 5 to 24, preferable in the range of 9 to 19, the preferred angle of each plate being 14; for convenience, I will hereinafter term these the crown plates. I have also found that thelength of each of the crown plates measured in the general direction of the longitudinal axis of the shank affects the performance of the crown and thatthis length must be from 10% to 28% of the length of the shank, the preferred length falling between 15% and 23%, the preferred value being 19% of the shank length; the plates must also be of sufficient width to be effective, and a plate of a width between 5% and 17% of the shank length is generally effective, the preferred value being in the range of 10%-12% of the shank length. The relative position of the crown plates with respect to the stock or pivot is also important in that from 20% to 50% of each of the crown plates (on an area basis) must extend forward of the center line of the stock or pivot, while I prefer that from 25% to 45% is forward of the stock or pivot, the preferred value being 35%; in each instance, the balance of the crown plates is aft of the pivot.

Each crown plate must also be spaced from the plane of the nukes a distance from 3% to 16% of the shank length, the distance being measured at an angle of approximately to the plane of the nukes outwardly from the center line of the pivot; the preferred range is from 5% to 14% with the preferred value being in the range of 8% to 10% of the shank length. In some instances, as when it is desired to provide additional support for the crown plates, it may be of advantage to continue each plate forward to abut against a nuke and to secure it to the nuke as by welding. The angle of the plates to the nuke and the spacing of the plates from the pivot may be such that the forward portion of the crown plates will each have to be divided to permit the shank to swing freely. Ir this construction is employed, then the preferred Values and ranges may not apply except as minimum values, e. g. at least 20% of the crown plate area will be forward of the pivot and the length of each plate will be at least 10% ofthe shank'length. The crown plates should be so disposed fore and aft of the pivot that, measured along the plate, the aft part is of a length from 5% to 18% of the shank length, the preferred range being '7% to 15% and the preferred value, 1112%; the fore part is of a length from 2% to 12% of theshank length, the preferred range being 4% toy 10% and the pre ferred value, 7%.

The preferred form of anchor is one constructed in accordance with my aforesaid patents but including the crown construction of this invention. Such an anchor will have, as is taught in my Patent 2,249,546, the flukes, shank and stock so proportioned and positioned' with respect to each other that at least twoV of the following characteristics will be. present:

(a) The total area of those portions of the flukes forward of the pivot a distance more than 20% of the shank length will bevat least 40% of the resistance area. 'I'he resistance area is the total area of the anchor projected onto a plane normal to the plane of the flukes with the shank in a normal operating relation to the flukes. The resistance area ofV thek anchor'illustrated in Figures 1-3 is shown in Figure 4 hereof.`

(b) A plane` passed through. the point of cable attachment to the shank and through the centers of area of only those portionsof: the nuke forward faces lying forward of thepivot a distance greater than 20% of the shank` length makes an angle with the plane of the forward iluke faces in the range of 40 to 60;

(c) A plane passed through said cable attachment point and the forward ends of the nukes makes anv angle with the projected fluke forward faces of less than 75;

(d) The stock will have an overall length at least twice the distance between the respective centers of area of the entire forward faces of the nukes.

Utilizing a twin.` fluke anchor constructed in accordance with my Patent 2,249,546 and. having a crown constructedias I have indicated, IV have been able to secure a positive engagement of the anchor with bottom without floating; an anchor is said to float (see my Patent 2,249,546, page 1, bottom of column 2) when the-flukes lie flatv on the ground surface or even inclined upward and do not fall into operatingr position even though the anchor is drawn over bottom. In addition, when freed from the bottom and brought to the surface, the anchor was practically free of any bottom substance. This makes the anchor easy to handle, for it can bel brought on board and stowed with a minimum, if not an entire absence, of cleaning. Further, being relatively clean, less weight must be handled'.

The nature of the invention will become further apparent upon considering a preferred structure embodying the present' invention., In the drawing accompanying and forming a part hereof,

Figure 1 is a plan view of an anchor constructed in accordance with the present invention.

Figure 2 is a side elevationof the anchor showing details of construction of thev crown.`

Figure 3 is a rear elevational view looking to the left of Figure 2.

Figure 4 is a view illustrating the definition of resistance area, the shank and fluke being in operating relation to one another, the anchor being viewed in such a direction that one is looking directly down the flukes. Figures 5 and 6 are each respectively similar to Figures 2 and 3 but showing a modified form of anchor. v

The anchor, as shown in the drawing, includes iiukes I0 and I I, the shank I2, stock I3 and crown plates I4 and I5.

'I'he fiukes are preferably secured in a co-planar relation on either side of the shank I2, the latter having an eye I6 at its forward end for attachment to an anchor chain or cable.

The iukes I0 and I I include reinforcing ribs I8 and I9 formed on the edge nearest the shank by bending of the fluke upon itself at an angle of approximately the-y nukes are identical but, when mounted in position, the ribs I8 extend in opposite directions. Each rib, at the rear end of the fluke, is parallel and adjacent to the shank to maintain the flukes in position and prevent undue. lateral movement between the shank and fluke. Of course, the flukes need not be constructed as I have indicatedA and one can employ castor fabricated structures, which I have indicated in my prior Patents 2,249,546, 2,282,566 and 2,320,966 andv in my various co-pending applications.

To secure the crown plates I4 and I5 in their correct position, spacer plates 20 and 2I are provided on each side of the shank I2 to confine the shank in position on the stock I3; the stock extends through a suitable aperture in the spacer plates (Figures 1, 2 and 3). Each spacer plate is welded' as at 3| tothe adjacent fluke and to its reinforcing rib; the crown plates Il! and I5 are each welded to the spacer plates as at 32. The crown plates act as stops to limit the swing of the shank and flukes relation to one another to provide for the correct angular relations between the shank and nukes when these are in operative position and, in the form shown, the crown plates are relieved as at 22 to permit of an adequate swing of the shank. By providing. opposite spacer plates secured to each fluke, adequate support is provided for the crown plates I 4 and I5 in the desired relation to the plane ofthe nukes. The spacer plates are made quite simply as by stamping; they provide an adequate support for the crown plates with a very low resistance to burial.

In that modifiedl form shown in Figures 4, 5 and 6, the spacer plates are formed from the material providing the ribs I8 and I9 on the nukes.

As I have indicated heretofore, in the preferred form of anchor the crown plates must be so positioned that from 20% to 50% of the area of each crown plate is forward of the stock, the preferred value being` 35% and the preferred range, 25% to 45%. The crown plates must be disposedv fore and aft. of the pivot and should preferably be of a length. equal to 19% of the shank length, the preferred range being 15% to 23% and inany case the preferred overall length between 10% and 26% of the shank length; in the anchor shown inthe drawing, the shank length is the distance from the center of the cable attachment eye I6 to the center of the stock. The crown plates must slope upwardly and away from the plane. of the iiukes at a relatively small acute angle, preferably 14 andv preferably one withn-thefrange of 9 to 19 and inany case. between5 and 24. Also, eachv crown plate must,

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for best results, be spaced from the center line of the pivot (measured in a direction substantially normal to the plane of the nukes) a distance equal to between 8% and 10% of the shank length, the preferred distance being in the range of from 5% to 14%, and in any case, within the range of 3% to 16% when the stock acts as the pivot mounting for the nukes, the stock center line or longitudinal axis can be utilized in making this measurement.

An anchor constructed within these teachings will engage promptly when drawn over bottom and will not noat (see the definition of noatingr hereinabove). Further, as has been indicated, the usual anchor, when engaged with a sticky mud bottom for any period of time and then removed, emerges from the water carrying a considerable amount of mud. The anchor ofthe present invention, when engaged in the same bottom, will emerge substantially free of any mud; for this reason, it is handled will less difficulty and with greater facility and can usually be brought inboard immediately without any extended cleaning operation.

I claim:

l. In an anchor of the twin nuke type having a shank with a forward and an after end; a stock; a pair of nukes pivoted at the after end of the shank with the shank between the nukes; said nukes having faces thereon substantially simultaneously engaging the ground in operative position; the improvement comprising a crown including a pair of substantially nat crown plates, each crown plate being supported in a position wherein said crown plate is spaced from the plane of the nukes a distance, measured outwardly from the center line of the stock and at substantially 90 to the plane of the nukes, of between about 3% and about 16% of the shank length with each crown plate sloping upwardly and rearwardly away from the plane of the nukes and being supported to permit bottom to now freely between the nuke and the underside of the crown plate, each crown plate having a width greater than about 5% of the shank length and a length of from about 10% to about 28% of the length of the shank and being positioned with between about 20% and about 50% of its area forward of the pivot.

2. In an anchor of the twin nuke type having a shank with a forward and an after end; a stock; a pair of nukes pivoted at the after end of the shank with the shank between the nukes; said nukes having faces thereon substantially simultaneously engaging the ground in operative position; the improvement comprising a crown at the after end of the shank including a pair of substantially nat crown plates, and a thin nat plate extending vertically to the plane of the nukes and parallel to the shank and supporting each crown plate in a position wherein each crown plate is spaced from the plane of the nukes a distance, measured outwardly from the center line of the stock and at substantially 90 to the plane of the nukes, of between about 3% and about 16% of the shank length and with the crown plate slop-ing upwardly and rearwardly away from the nukes at an angle of from about 5 to about 24 to the plane of the nukes, each crown plate having a width of between about 5% to about 17% of the shank length and a length of from about 10% to about 28% of the length of the shank.

3. In an anchor of the twin nuke type having a shank with a forward and an after end; a stock; a pair of nukes pivoted at the after end of the shank with the shank between the nukes and movable therebetween in a plane normal to the nukes; said nukes having faces thereon substantially simultaneously engaging the ground in operative position; the improvement comprising a crown at the after end of the shank including a pair of substantially nat crown plates, each crown plate being supported in a position wherein said crown plate is spaced from the plane of the nukes a distance, measured outwardly from the center line of the stock andv at substantially 90 to the plane lof the nukes of between about 3% and about 16% of the shank lengthv with the crown plate sloping upwardly and rearwardly away from the nukes at an angle of from about 5 to about 24 to the plane of the nukes to permit bottom to now freely between the nuke and the underside of the crown plate, each crown plate having a length of from about 10% to :about 28% of the length of the shank and Va width greater than about 5% of the shank iength and being positioned with between about 20% and about 50% of its larea forward of the pivot.

4. In an anchor of the twin nuke type having a shank with a forward and an after end; a stock; a pair of nukes pivoted at the after end of the shank with the shank between the nukes; said nukes having' faces thereon substantially simultaneously engaging the ground in operative position; the improvement comprising a crown at the after end of the shank including a pair of substantially nat crown plates, each crown plate being supported centrally of the nukes and in a position wherein said crown plate is spaced from the plane of the nukes a distancey measured outwardly from the center line of the stock and at substantially 90Q to plane of the nukes, of between about 3% and about `16% of the shank length with each crown plate sloping upwardly and rearwardly away from the plane of the nukes, each crown plate having a width greater than about 5% `of the shank length and a length of from about 10% to about 28% of the length of the shank.

5. In an anchor of the twin nuke type having a shank having a forward and an after end with a .point `of cable attachment at said forward end, a stock, a pair of nukes, and a pivot mounting said nukes at said after end of said shank with said nukes extending toward said forward end and with said shank between said nukes, said nukes substantially simultaneously engaging the ground when in operative position; said shank and nukes being so proportioned and positioned that the total area of those portions of said nukes forward of said pivot a distance more than 20% of the shank length is at least 40% of the resistance area, said stock having an overall length at least twice the distance between the respective centers of area of the entire forward faces of said nukes, and a plane passed through said cable attachment point and the forward ends of said nukes in operative position makes an angle with the projected nuke forward faces of less than the improvement comprising a crown at the after end of the shank including a pair of substantially nat crown plates, each crown plate being supported in a position wherein said crown plate is spaced from the plane of the nukes a distance, measured outwardly from the center line of the stock and at substantially to plane of the nukes, of between about 3% and about 16% of the shank length with each crown plate sloping upwardly and rearwardly away from the plane of the nukes, each crown plate having a width greater than about 5% of the shank length 'Z' and a length of from-about to-about' 28%- of the lengthof the shank.

6. In an` anchorr of the twin fluke type. having' a shank having a forward and an afterl end with a pointof cable attachment. at said: forward ends a stock, a. pair' of nukes, and' a. pivot mounting saidflakes`l at said after end of; said. shankzwith said ukes extending toward? said` forward',y end and with said shank movable. between said ukes in al plane normal` tothe: ulees, said nukes substantial'ly simultaneously engaging. the ground when. in. operative position; said' shank4 and nukes being so proportioned' and positioned that the total area of thosev portions of said nukes forward of saidpivot a distance more than of the shank length is at least 401% of the resistance area, said stool; having an overall length at least twice the distance between. the'respective centers of area of the entire forward faces of said nukes., and a plane passed through said cableattachment point andthe forward. ends ofsaid flukes in operative position makes an angle with the projected uke forward faces of less` than the irnprovernent comprising a crown at the after endof the shank including, a pail. of. substantially flat 25 each crowny plate is spaced from the plane of the flukes' a distance measured outwardly from the centerline ot the stock and at substantially toy plane of the ukes, of between about 3% and about 16% of the shank length with the crown plate sloping upwardly and rearwardly away from the flukes at an angle of from about 5 to about 24 to the plane of the flukes to permit bottom to W freely* between the flukes and the undeiside of lthe crown plate, each crown plate haw'ng a width greater than about 5% of the shank; length anda length of from about. 10% to about 28% of the length of the shank and :being positioned with between about 20% and` about 50%. of its area forward of the pivot,

RICHARD S, DANFORTH.

References Cited in the file of this patent UNITED STATES PATENTS Number Re. 21,841 31,726 527,060 670,368 2,249,546 2,282,566 2,354,666 2,496,315 

